1. Field of the Invention
The present invention relates to a wiring structure of a semiconductor device, and more particularly to a semiconductor device designed to improve contact characteristics between a capacitor and a wiring electrically connected to lower and upper electrodes thereof.
2. Description of the Related Art
Generally, the upper and lower electrodes of the capacitor provided in the semiconductor device are electrically connected to a wiring, a plug or the like thereabove. Such a technology is disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2001-274328, 2001-274340 or the like.
In the above structure, for example, the wiring is bulged to the outside of the upper and lower electrodes of the capacitor to be formed thereabove. In this case, if a wiring groove for providing the wiring is formed to a prescribed depth or more, there is a fear that a bottom surface of the wiring will be brought into planar (full) contact with a layer (film) selected from the upper electrode, a capacitive insulating film, and the lower electrode of the capacitor. If the wiring is brought into planar contact with the capacitor, film stress occurs on a contact interface between the wiring and one of the layers of the capacitor, easily causing film peeling-off failures.
Additionally, if the wiring groove is formed to the prescribed depth or more, there is a fear that the wiring for electrically interconnecting via-plugs electrically connected to electrodes of similar polarities originally will be brought into electric contact with electrodes of different polarities. Specifically, there is a fear that the wiring electrically connected only to the upper electrode of the capacitor will be brought into electric contact with the lower electrode thereof. If the wiring electrically connected to the upper electrode is brought into electric contact with the lower electrode, short-circuiting occurs between the lower and upper electrodes. In other words, an electric characteristic failure of the capacitor (characteristic deterioration failure of the capacitor) occurs.